In diagnosing and treating certain medical conditions, such as potentially cancerous tumors, it may be desirable to perform a biopsy, in which a specimen of the suspicious tissue is removed for pathological examination and analysis. In many instances, the suspicious tissue is located at a subcutaneous site, such as inside a human breast. To minimize surgical intrusion into a patient's body, it is desirable to be able to insert a small instrument into the body to gain access to the desired location for inspection and for extraction of a biopsy specimen.
Body tissue is often deformable, so that insertion of a needle or other device into a patient's tissues will often deform or displace the tissue through which the needle or other device moves. Tissues of interest, such as nodules, masses, tumors and the like, which are typically the desired targets of a biopsy sample, may be readily displaced, pushed aside or otherwise deformed during biopsy procedures, making it likely that some or all of the desired target tissue may be missed during the biopsy procedure, thereby increasing the likelihood of misdiagnosis of the condition that led to the need for the biopsy.
In extraction of a biopsy specimen with a probe, it may be desirable to anchor the probe in a desired position so as to insure that the probe remains in a proper position relative to the suspect tissue during manipulations and activities before and during the actual acquisition of the biopsy sample. In addition, it may be desirable to isolate tissue from neighboring healthy tissue in order to ensure that no diseased or abnormal tissue remains outside the sampled volume. Thus, the volume of tissue isolated may be larger than the minimum necessary so as to obtain margins of tissue free of disease for pathological diagnosis.
Electrosurgical techniques have been used in a variety of circumstances, including certain types of biopsy procedures. In electrosurgery, high frequency electrical energy is applied through a primary electrode to patient tissue. The electrical energy flows through the tissue to a return electrode that is in contact with the patent's tissue. Typically, the return electrode is attached to the patient at a point remote from where the primary electrode contacts the tissue. The tissue adjacent the primary electrode is ablated, to form an opening in the tissue.
When electrically activated, the electrode ablates the tissue adjacent the electrode, to produce a tissue opening which provides access to tissue to be taken in a biopsy sample. Guidance of the electrode tip to the desired site within a patient's body may be through stereotactic, radiological, ultrasonic, magnetic resonance imaging (MRI), or other means. However, there is frequently a delay between the positioning of the device and the taking of the biopsy sample, so that the device or tissue may move and prevent acquisition of the desired tissue. Accordingly, there is need in the art for means to mark a target site within a patient's body and for means to anchor the biopsy device in a proper location.
The tissue to be sampled or removed from the patient will often comprise a volume larger than the volume of the biopsy probe to obtain disease-free margins for pathological diagnosis. Accordingly, means for obtaining tissue samples larger than the probe itself are desired. In addition, it is of clinical interest to determine the extent of a diseased or abnormal portion of the tissue, and it is often desired that a border of normal tissue, surrounding any abnormal tissue present, be removed as well. It is further desired that the tissue to be removed be isolated from the body to prevent migration of diseased or abnormal tissue into other locations of the patient's body.
Accordingly, there is need in the art for devices and methods for accessing a desired site within a patient's body without displacing target body tissue, for anchoring devices at a desired site to prevent movement of such devices after arrival at a desired site, for isolating tissue, and for taking biopsy specimens from a patient.